module Klaxon

Insert a programmable interactive warning prompt for developers before taking dangerous or destructive action.

Example:

Klaxon.alert banner: 'Delete', description: 'About to delete files!' do
  system "rm -rf"
end

# prints to STDERR...
 _____       _      _       
|  __ \     | |    | |      
| |  | | ___| | ___| |_ ___ 
| |  | |/ _ \ |/ _ \ __/ _ \
| |__| |  __/ |  __/ |_  __/
|_____/ \___|_|\___|\__\___|

About to delete files!
To continue, press ENTER. To abort, press Ctrl+C...

Constants

ENTER
RANDOM
VERSION
YESNO

Public Class Methods

alert(banner: nil, description: nil, color: nil, type: nil, ci: nil, &dangerous) click to toggle source

Issues the alert prompt, unless running in a CI environment. The prompt is always to STDERR.

When run with a block, denying the prompt will simply not call the block. When run without a block, denying will cause a system exit.

:banner: - A large block banner displayed figlet-style
:description: - Paragraph text for the prompt, with line feeds preserved
:color: - A symbol like :red or :yellow which will color the whole prompt
:type: - Either :enter (the default), :yesno, :random, or literal text
:ci: - If nil, auto-detect a CI environment from the ENV; if true, behave like a CI environment; if false, halt if it is a CI environment
:dangerous: - A block to call or not call–if omitted, the method will return true or exit

# File lib/klaxon.rb, line 44
def self.alert(banner: nil, description: nil, color: nil, type: nil, ci: nil, &dangerous)
  execute = proc do
    if dangerous
      return dangerous.call
    else
      return true
    end
  end

  halt = proc do
    if dangerous
      STDERR.puts "\nSkipping.".colorize color
      return false
    else
      STDERR.puts "\nExiting."
      exit 1
    end
  end

  prompt = proc do |msg,&ok|
    STDERR.print msg
    begin
      if ok[STDIN.gets.chomp.downcase]
        execute.call
      end
    rescue Interrupt
    end

    halt.call
  end

  if ci == true
    execute.call
  elsif !STDIN.isatty && (ENV['CI'] || ENV['JENKINS_URL'])
    if ci != false
      execute.call
    else
      halt.call
    end
  end

  if banner
    STDERR.puts
    STDERR.puts Artii::Base.new.asciify(banner).each_line.map {|line| "    " + line[0..TermInfo.screen_width-4] }.join.colorize color
    STDERR.puts
  end

  if description
    STDERR.puts description.colorize color
  end

  case type
  when ENTER, nil
    prompt.call "To continue, press ENTER. To abort, press Ctrl+C..." do
      true
    end
  when YESNO
    prompt.call "Continue? [y/N]: " do |val|
      ['y', 'yes'].include?(val)
    end
  when RANDOM
    digits = SecureRandom.hex(2)
    prompt.call "To continue, type #{digits.upcase.split(//).join(" ")}\n> " do |val|
      val.gsub(/\s+/, '') == digits
    end
  else
    prompt.call "To continue, type \"#{type}\"\n> " do |val|
      val == type
    end
  end
end